On Tue, Nov 29, 2011 at 8:42 PM, Heiko Stübner <heiko@xxxxxxxxx> wrote:
> Hi Shubhrajyoti,
>
> Am Dienstag, 29. November 2011, 15:59:29 schrieb Shubhrajyoti Datta:
>> Hi Heiko,
>>
>> On Tue, Nov 29, 2011 at 5:54 PM, Heiko Stübner <heiko@xxxxxxxxx> wrote:
>> > There exist tilt switches that simply report their tilt-state via some
>> > gpios.
>> >
>> > The number and orientation of their axes can vary depending on the switch
>> > used and the build of the device. Also two or more one-axis switches
>> > could be combined to provide multi-dimensional orientation.
>> >
>> > One example of a device using such a switch is the family of Qisda
>> > ebook readers, where the switch provides information about the
>> > landscape / portrait orientation of the device. The example in
>> > Documentation/input/gpio-tilt.txt documents exactly this one-axis device.
>> >
>> > Signed-off-by: Heiko Stuebner <heiko@xxxxxxxxx>
>> > ---
>> > changes since v2: use module_platform_driver
>> > changes since v1: address comments from Dmitry Torokhov
>> > * bdev -> tdev
>> > * report initial axis state during open and not during probe
>> > * don't clone platform data and use the original instead
>> >
>> > Documentation/input/gpio-tilt.txt | 103 ++++++++++++++++
>> > drivers/input/misc/Kconfig | 14 ++
>> > drivers/input/misc/Makefile | 1 +
>> > drivers/input/misc/gpio_tilt_polled.c | 214
>> > +++++++++++++++++++++++++++++++++ include/linux/gpio_tilt.h
>> > | 73 +++++++++++
>> > 5 files changed, 405 insertions(+), 0 deletions(-)
>> > create mode 100644 Documentation/input/gpio-tilt.txt
>> > create mode 100644 drivers/input/misc/gpio_tilt_polled.c
>> > create mode 100644 include/linux/gpio_tilt.h
>> >
>> > diff --git a/Documentation/input/gpio-tilt.txt
>> > b/Documentation/input/gpio-tilt.txt new file mode 100644
>> > index 0000000..06d60c3
>> > --- /dev/null
>> > +++ b/Documentation/input/gpio-tilt.txt
>> > @@ -0,0 +1,103 @@
>> > +Driver for tilt-switches connected via GPIOs
>> > +============================================
>> > +
>> > +Generic driver to read data from tilt switches connected via gpios.
>> > +Orientation can be provided by one or more than one tilt switches,
>> > +i.e. each tilt switch providing one axis, and the number of axes
>> > +is also not limited.
>> > +
>> > +
>> > +Data structures:
>> > +----------------
>> > +
>> > +The array of struct gpio in the gpios field is used to list the gpios
>> > +that represent the current tilt state.
>> > +
>> > +The array of struct gpio_tilt_axis describes the axes that are reported
>> > +to the input system. The values set therein are used for the
>> > +input_set_abs_params calls needed to init the axes.
>> > +
>> > +The array of struct gpio_tilt_state maps gpio states to the
>> > corresponding +values to report. The gpio state is represented as a
>> > bitfield where the +bit-index corresponds to the index of the gpio in
>> > the struct gpio array. +In the same manner the values stored in the axes
>> > array correspond to +the elements of the gpio_tilt_axis-array.
>> > +
>> > +
>> > +Example:
>> > +--------
>> > +
>> > +Example configuration for a single TS1003 tilt switch that rotates
>> > around +one axis in 4 steps and emitts the current tilt via two GPIOs.
>> > +
>> > +static int sg060_tilt_enable(struct device *dev) {
>> > + /* code to enable the sensors */
>> > +};
>> > +
>> > +static void sg060_tilt_disable(struct device *dev) {
>> > + /* code to disable the sensors */
>> > +};
>> > +
>> > +static struct gpio sg060_tilt_gpios[] = {
>> > + { SG060_TILT_GPIO_SENSOR1, GPIOF_IN, "tilt_sensor1" },
>> > + { SG060_TILT_GPIO_SENSOR2, GPIOF_IN, "tilt_sensor2" },
>> > +};
>> > +
>> > +static struct gpio_tilt_state sg060_tilt_states[] = {
>> > + {
>> > + .gpios = (0 << 1) | (0 << 0),
>> > + .axes = (int[]) {
>> > + 0,
>> > + },
>> > + }, {
>> > + .gpios = (0 << 1) | (1 << 0),
>> > + .axes = (int[]) {
>> > + 1, /* 90 degrees */
>> > + },
>> > + }, {
>> > + .gpios = (1 << 1) | (1 << 0),
>> > + .axes = (int[]) {
>> > + 2, /* 180 degrees */
>> > + },
>> > + }, {
>> > + .gpios = (1 << 1) | (0 << 0),
>> > + .axes = (int[]) {
>> > + 3, /* 270 degrees */
>> > + },
>> > + },
>> > +};
>> > +
>> > +static struct gpio_tilt_axis sg060_tilt_axes[] = {
>> > + {
>> > + .axis = ABS_RY,
>> > + .min = 0,
>> > + .max = 3,
>> > + .fuzz = 0,
>> > + .flat = 0,
>> > + },
>> > +};
>> > +
>> > +static struct gpio_tilt_platform_data sg060_tilt_pdata= {
>> > + .gpios = sg060_tilt_gpios,
>> > + .nr_gpios = ARRAY_SIZE(sg060_tilt_gpios),
>> > +
>> > + .axes = sg060_tilt_axes,
>> > + .nr_axes = ARRAY_SIZE(sg060_tilt_axes),
>> > +
>> > + .states = sg060_tilt_states,
>> > + .nr_states = ARRAY_SIZE(sg060_tilt_states),
>> > +
>> > + .debounce_interval = 100,
>> > +
>> > + .poll_interval = 1000,
>> > + .enable = sg060_tilt_enable,
>> > + .disable = sg060_tilt_disable,
>> > +};
>> > +
>> > +static struct platform_device sg060_device_tilt = {
>> > + .name = "gpio-tilt-polled",
>> > + .id = -1,
>> > + .dev = {
>> > + .platform_data = &sg060_tilt_pdata,
>> > + },
>> > +};
>> > diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
>> > index 22d875f..e53b443 100644
>> > --- a/drivers/input/misc/Kconfig
>> > +++ b/drivers/input/misc/Kconfig
>> > @@ -179,6 +179,20 @@ config INPUT_APANEL
>> > To compile this driver as a module, choose M here: the module
>> > will be called apanel.
>> >
>> > +config INPUT_GPIO_TILT_POLLED
>> > + tristate "Polled GPIO tilt switch"
>> > + depends on GENERIC_GPIO
>> > + select INPUT_POLLDEV
>> > + help
>> > + This driver implements support for tilt switches connected
>> > + to GPIO pins that are not capable of generating interrupts.
>> > +
>> > + The list of gpios to use and the mapping of their states
>> > + to specific angles is done via platform data.
>> > +
>> > + To compile this driver as a module, choose M here: the
>> > + module will be called gpio_tilt_polled.
>> > +
>> > config INPUT_IXP4XX_BEEPER
>> > tristate "IXP4XX Beeper support"
>> > depends on ARCH_IXP4XX
>> > diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
>> > index a244fc6..90070c1 100644
>> > --- a/drivers/input/misc/Makefile
>> > +++ b/drivers/input/misc/Makefile
>> > @@ -23,6 +23,7 @@ obj-$(CONFIG_INPUT_CMA3000_I2C) +=
>> > cma3000_d0x_i2c.o obj-$(CONFIG_INPUT_COBALT_BTNS) +=
>> > cobalt_btns.o obj-$(CONFIG_INPUT_DM355EVM) += dm355evm_keys.o
>> > obj-$(CONFIG_HP_SDC_RTC) += hp_sdc_rtc.o
>> > +obj-$(CONFIG_INPUT_GPIO_TILT_POLLED) += gpio_tilt_polled.o
>> > obj-$(CONFIG_INPUT_IXP4XX_BEEPER) += ixp4xx-beeper.o
>> > obj-$(CONFIG_INPUT_KEYSPAN_REMOTE) += keyspan_remote.o
>> > obj-$(CONFIG_INPUT_KXTJ9) += kxtj9.o
>> > diff --git a/drivers/input/misc/gpio_tilt_polled.c
>> > b/drivers/input/misc/gpio_tilt_polled.c new file mode 100644
>> > index 0000000..ebc3f08
>> > --- /dev/null
>> > +++ b/drivers/input/misc/gpio_tilt_polled.c
>> > @@ -0,0 +1,214 @@
>> > +/*
>> > + * Driver for tilt switches connected via GPIO lines
>> > + * not capable of generating interrupts
>> > + *
>> > + * Copyright (C) 2011 Heiko Stuebner <heiko@xxxxxxxxx>
>> > + *
>> > + * based on: /drivers/input/keyboard/gpio_keys_polled.c
>> > + *
>> > + * Copyright (C) 2007-2010 Gabor Juhos <juhosg@xxxxxxxxxxx>
>> > + * Copyright (C) 2010 Nuno Goncalves <nunojpg@xxxxxxxxx>
>> > + *
>> > + * This program is free software; you can redistribute it and/or modify
>> > + * it under the terms of the GNU General Public License version 2 as
>> > + * published by the Free Software Foundation.
>> > + */
>> > +
>> > +#include <linux/kernel.h>
>> > +#include <linux/module.h>
>> > +#include <linux/init.h>
>> > +#include <linux/slab.h>
>> > +#include <linux/input.h>
>> > +#include <linux/input-polldev.h>
>> > +#include <linux/ioport.h>
>> > +#include <linux/platform_device.h>
>> > +#include <linux/gpio.h>
>> > +#include <linux/gpio_tilt.h>
>> > +
>> > +#define DRV_NAME "gpio-tilt-polled"
>> > +
>> > +struct gpio_tilt_polled_dev {
>> > + struct input_polled_dev *poll_dev;
>> > + struct device *dev;
>> > + struct gpio_tilt_platform_data *pdata;
>> > +
>> > + int last_state;
>> > +
>> > + int threshold;
>> > + int count;
>> > +};
>> > +
>> > +static void gpio_tilt_polled_poll(struct input_polled_dev *dev)
>> > +{
>> > + struct gpio_tilt_polled_dev *tdev = dev->private;
>> > + struct gpio_tilt_platform_data *pdata = tdev->pdata;
>> > + struct input_dev *input = dev->input;
>> > + struct gpio_tilt_state *tilt_state = NULL;
>> > + int state, i;
>> > +
>> > + if (tdev->count < tdev->threshold) {
>>
>> Nitpick : the braces are not necessary.
> hmm ... for me it's easier to read if the style of the braces does not change
> between if and else, i.e. both with or without braces.
> And the kernel CodingStyle-file seems also to be in my favor ;-)
> [starting from line 169].
I see thanks for correcting.
>
>> > + tdev->count++;
>> > + } else {
>> > + state = 0;
>> > + for (i = 0; i < pdata->nr_gpios; i++)
>> > + state |= (!!gpio_get_value(pdata->gpios[i].gpio)
>> > << i); +
>> > + if (state != tdev->last_state) {
>> > + for (i = 0; i < pdata->nr_states; i++)
>> > + if (pdata->states[i].gpios == state)
>> > + tilt_state = &pdata->states[i];
>> > +
>> > + if (tilt_state) {
>> > + for (i = 0; i < pdata->nr_axes; i++)
>> > + input_report_abs(input,
>> > +
>> > pdata->axes[i].axis, +
>> > tilt_state->axes[i]); +
>> > + input_sync(input);
>> > + }
>> > +
>> > + tdev->count = 0;
>> > + tdev->last_state = state;
>> > + }
>> > + }
>> > +}
>> > +
>> > +static void gpio_tilt_polled_open(struct input_polled_dev *dev)
>> > +{
>> > + struct gpio_tilt_polled_dev *tdev = dev->private;
>> > + struct gpio_tilt_platform_data *pdata = tdev->pdata;
>> > +
>> > + if (pdata->enable)
>> > + pdata->enable(tdev->dev);
>> > +
>> > + /* report initial state of the axes */
>> > + tdev->last_state = -1;
>> > + tdev->count = tdev->threshold;
>> > + gpio_tilt_polled_poll(tdev->poll_dev);
>> > +}
>> > +
>> > +static void gpio_tilt_polled_close(struct input_polled_dev *dev)
>> > +{
>> > + struct gpio_tilt_polled_dev *tdev = dev->private;
>> > + struct gpio_tilt_platform_data *pdata = tdev->pdata;
>> > +
>> > + if (pdata->disable)
>> > + pdata->disable(tdev->dev);
>> > +}
>> > +
>> > +static int __devinit gpio_tilt_polled_probe(struct platform_device
>> > *pdev) +{
>> > + struct gpio_tilt_platform_data *pdata = pdev->dev.platform_data;
>> > + struct device *dev = &pdev->dev;
>> > + struct gpio_tilt_polled_dev *tdev;
>> > + struct input_polled_dev *poll_dev;
>> > + struct input_dev *input;
>> > + int error, i;
>> > +
>> > + if (!pdata || !pdata->poll_interval)
>> > + return -EINVAL;
>>
>> Could we have a default poll interval if passed 0 ?
>> Feel free to ignore if you feel otherwise.
> For me either way is fine but I'm not sure what would be a generic
> enough default value for most cases (500, 1000 ? ).
>
I was thinking that just because someone doesn't populate the timeout gets
penalised max ie failure of probe.
1000 looks good to me also your documentation suggests so . However I leave the
decision to you.
>> > +
>> > + tdev = kzalloc(sizeof(struct gpio_tilt_polled_dev), GFP_KERNEL);
>> > + if (!tdev) {
>> > + dev_err(dev, "no memory for private data\n");
>> > + return -ENOMEM;
>> > + }
>> > +
>> > + error = gpio_request_array(pdata->gpios, pdata->nr_gpios);
>> > + if (error) {
>> > + dev_err(dev,
>> > + "Could not request tilt GPIOs: %d\n", error);
>> > + goto err_free_tdev;
>> > + }
>> > +
>> > + poll_dev = input_allocate_polled_device();
>> > + if (!poll_dev) {
>> > + dev_err(dev, "no memory for polled device\n");
>> > + error = -ENOMEM;
>> > + goto err_free_gpios;
>> > + }
>> > +
>> > + poll_dev->private = tdev;
>> > + poll_dev->poll = gpio_tilt_polled_poll;
>> > + poll_dev->poll_interval = pdata->poll_interval;
>> > + poll_dev->open = gpio_tilt_polled_open;
>> > + poll_dev->close = gpio_tilt_polled_close;
>> > +
>> > + input = poll_dev->input;
>> > +
>> > + input->name = pdev->name;
>> > + input->phys = DRV_NAME"/input0";
>> > + input->dev.parent = &pdev->dev;
>> > +
>> > + input->id.bustype = BUS_HOST;
>> > + input->id.vendor = 0x0001;
>> > + input->id.product = 0x0001;
>> > + input->id.version = 0x0100;
>> > +
>> > + __set_bit(EV_ABS, input->evbit);
>> > + for (i = 0; i < pdata->nr_axes; i++) {
>> > + input_set_abs_params(input, pdata->axes[i].axis,
>> > + pdata->axes[i].min,
>> > pdata->axes[i].max, +
>> > pdata->axes[i].fuzz, pdata->axes[i].flat); + }
>> > +
>> > + tdev->threshold = DIV_ROUND_UP(pdata->debounce_interval,
>> > + pdata->poll_interval);
>> > +
>> > + tdev->poll_dev = poll_dev;
>> > + tdev->dev = dev;
>> > + tdev->pdata = pdata;
>> > +
>> > + error = input_register_polled_device(poll_dev);
>> > + if (error) {
>> > + dev_err(dev, "unable to register polled device,
>> > err=%d\n", + error);
>> > + goto err_free_polldev;
>> > + }
>> > +
>> > + platform_set_drvdata(pdev, tdev);
>> > +
>> > + return 0;
>> > +
>> > +err_free_polldev:
>> > + input_free_polled_device(poll_dev);
>> > +err_free_gpios:
>> > + gpio_free_array(pdata->gpios, pdata->nr_gpios);
>> > +err_free_tdev:
>> > + kfree(tdev);
>> > +
>> > + return error;
>> > +}
>> > +
>> > +static int __devexit gpio_tilt_polled_remove(struct platform_device
>> > *pdev) +{
>> > + struct gpio_tilt_polled_dev *tdev = platform_get_drvdata(pdev);
>> > + struct gpio_tilt_platform_data *pdata = tdev->pdata;
>> > +
>> > + platform_set_drvdata(pdev, NULL);
>> > +
>> > + input_unregister_polled_device(tdev->poll_dev);
>> > + input_free_polled_device(tdev->poll_dev);
>> > +
>> > + gpio_free_array(pdata->gpios, pdata->nr_gpios);
>> > +
>> > + kfree(tdev);
>> > +
>> > + return 0;
>> > +}
>> > +
>> > +static struct platform_driver gpio_tilt_polled_driver = {
>> > + .probe = gpio_tilt_polled_probe,
>> > + .remove = __devexit_p(gpio_tilt_polled_remove),
>> > + .driver = {
>> > + .name = DRV_NAME,
>> > + .owner = THIS_MODULE,
>> > + },
>> > +};
>> > +
>> > +module_platform_driver(gpio_tilt_polled_driver);
>> > +
>> > +MODULE_LICENSE("GPL v2");
>> > +MODULE_AUTHOR("Heiko Stuebner <heiko@xxxxxxxxx>");
>> > +MODULE_DESCRIPTION("Polled GPIO tilt driver");
>> > +MODULE_ALIAS("platform:" DRV_NAME);
>> > diff --git a/include/linux/gpio_tilt.h b/include/linux/gpio_tilt.h
>> > new file mode 100644
>> > index 0000000..809fe93
>> > --- /dev/null
>> > +++ b/include/linux/gpio_tilt.h
>> > @@ -0,0 +1,73 @@
>> > +#ifndef _GPIO_TILT_H
>> > +#define _GPIO_TILT_H
>> > +
>> > +/**
>> > + * struct gpio_tilt_axis - Axis used by the tilt switch
>> > + * @axis: Constant describing the axis, e.g. ABS_X
>> > + * @min: minimum value for abs_param
>> > + * @max: maximum value for abs_param
>> > + * @fuzz: fuzz value for abs_param
>> > + * @flat: flat value for abs_param
>> > + */
>> > +struct gpio_tilt_axis {
>> > + int axis;
>> > + int min;
>> > + int max;
>> > + int fuzz;
>> > + int flat;
>> > +};
>> > +
>> > +/**
>> > + * struct gpio_tilt_state - state description
>> > + * @gpios: bitfield of gpio target-states for the value
>> > + * @axes: array containing the axes settings for the gpio
>> > state + * The array indizes must correspond to the
>> > axes defined + * in platform_data
>> > + *
>> > + * This structure describes a supported axis settings
>> > + * and the necessary gpio-state which represent it.
>> > + *
>> > + * The n-th bit in the bitfield describes the state of the n-th GPIO
>> > + * from the gpios-array defined in gpio_regulator_config below.
>> > + */
>> > +struct gpio_tilt_state {
>> > + int gpios;
>> > + int *axes;
>> > +};
>> > +
>> > +/**
>> > + * struct gpio_tilt_platform_data
>> > + * @gpios: Array containing the gpios determining the tilt
>> > state + * @nr_gpios: Number of gpios
>> > + * @axes: Array of gpio_tilt_axis descriptions
>> > + * @nr_axes: Number of axes
>> > + * @states: Array of gpio_tilt_state entries describing
>> > + * the gpio state for specific tilts
>> > + * @nr_states: Number of states available
>> > + * @debounce_interval: debounce ticks interval in msecs
>> > + * @poll_interval: polling interval in msecs - for polling driver
>> > only + * @enable: callback to enable the tilt switch
>> > + * @disable: callback to disable the tilt switch
>> > + *
>> > + * This structure contains gpio-tilt-switch configuration
>> > + * information that must be passed by platform code to the
>> > + * gpio-tilt input driver.
>> > + */
>> > +struct gpio_tilt_platform_data {
>> > + struct gpio *gpios;
>> > + int nr_gpios;
>> > +
>> > + struct gpio_tilt_axis *axes;
>> > + int nr_axes;
>> > +
>> > + struct gpio_tilt_state *states;
>> > + int nr_states;
>> > +
>> > + int debounce_interval;
>> > +
>> > + unsigned int poll_interval;
>> > + int (*enable)(struct device *dev);
>> > + void (*disable)(struct device *dev);
>> > +};
>> > +
>> > +#endif
>> > --
>> > 1.7.5.4
>> >
>> > --
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